The Food and Drug Administration consults a panel of outside experts about drug approvals and other decisions. The agency is not required to follow the panel's recommendation, but often does.

Below are some facts about FDA advisory committees.

WHAT ARE COMMITTEES?

The FDA is advised by 49 committees and panels with more than 600 members, each with a certain area of expertise. The committees provide independent, expert advice on approvals of drugs and medical devices, and also on general policy matters.

WHO IS ON COMMITTEES?

Scientific experts such as doctors and biostatisticians serve on committees. They must be able to analyze complex scientific data and "understand its public health significance."

Committees also have a consumer and patient representative, as well as an industry representative who can't vote, but can speak and ask questions. Some critics contend even nonvoting members can influence panel discussions.

LEGAL GUIDELINES FOR PANELS

The make-up of the panels is governed by the Federal Advisory Committee Act, which applies to all government agencies. The rules try to ensure the population as a whole is represented, including women, minorities, those with disabilities and different geographic regions of the country.

Each potential member has to provide information about financial holdings, employment, research grants and contracts, and any other potential conflicts of interest which could bar participation.

Currently, department heads at a hospital or university are barred if any of their staff or their institution have a conflict, leading to calls the rules are too broad.

The FDA is not required to disclose conflicts of interest unless it grants someone a waiver. Critics doubt that the FDA can discover a violation of the rules if someone decides to hide a potential conflict.

WHAT ARE WAIVERS

Currently, panel members with financial ties of over $50,000 to a drugmaker or a competitor are automatically barred from serving on a panel for that company. Those with smaller financial ties may still advise on the drug - though the agency must justify the move in a waiver letter, which must be approved by the relevant FDA department.

Federal guidelines cap the number of waivers the agency can use at about 13 percent for 2010, with the figure set to diminish over time.

HOW FDA FINDS PANELISTS

Professional societies, industry, consumer and patient advocacy groups and the FDA itself can nominate panel members based on their work in the field. People can also self-nominate. Nominees must go through a vetting process for conflicts of interest and scientific expertise, after which they can serve for up to four years.

WHY PANELISTS DO IT

All advisory members become "Special Government Employees" and get a salary for each meeting day, as well as travel and daily costs.

Many panel members said the salary rarely covers the hardship of frequent, possibly cross-country trips, the lost salary at regular jobs, and the need for extensive preparation ahead of each meeting.

While serving as an FDA panelist could be a slight boost to credibility and resume, most members are already established experts in their field, and often do it simply to have a more direct effect on medical practice.